Download or read book The Change of Pressure Distribution on Parachute Canopies During Inflation written by H.-D. Mlzig and published by . This book was released on 1965 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: For a design engineer strength calculation is a prerequisite for completion of design. The parachute designer however encounters great difficulty. Theory provides no means for calculation and almost no data is available of measurements under dynamic conditions to permit adequate strength calculation. The rapidly changing dynamic forces can vastly exceed the steady state forces. Great efforts have been made to predict stresses in a parachute canopy. The latest work for a parachute stress analysis was conducted by H.G. Heinrich and L.R. Jamison [1] and is a great advance. Contrary to former attempts it includes parachute shapes during inflation of the canopy. The great disadvantage of all theoretical attempts is that the actual stress distribution in a canopy is still unknown. No method has yet been found to measure stresses directly in many parts of a canopy.
Download or read book Pressure Distribution During Parachute Opening written by H. D. Melzig and published by . This book was released on 1966 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation and correlative analysis were conducted to determine the pressure distribution over the surface of parachute canopies during the period of inflation for the infinite mass case and to correlate pressure coefficients with inflating canopy shapes. Parachute canopy models of Circular Flat, 10% Extended Skirt, Ringslot, and Ribbon designs were tested under infinite mass conditions in a 9 x 12 ft low speed wind tunnel. External and internal pressure values were measured at various locations over the surface of the model canopies throughout the period of inflation, and generalized canopy profile shapes were obtined by means of photographic analysis.
Download or read book Pressure Distribution During Parachute Opening written by H. D. Melzig and published by . This book was released on 1969 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted to determine the differential pressure distribution over the surface of parachute canopies during the period of inflation under mass conditions. Full scale parachute canopies of the circular flat, 10% extended skirt, ringslot and ribbon types were utilized during the free-flight test program, and differential pressures on the gore centerline and on the cord line were measured by means of four pressure transducers distributed over the canopy in equal distances from the skirt to the vent. In order to analyze the relationships and dependencies between the pressure distribution, projected canopy area, canopy shape, generated force, and dynamic pressure, graphical displays of these quantities were made as a function of time for each type of parachute canopy. The results of the pressure distribution measurements permit a better understanding of the physical nature of the dynamic process of parachute inflation. The stress distribution in a parachute canopy can be calculated if the corresponding canopy shape is known. For this purpose, the evolvement of the canopy shape with the corresponding time is presented for each of the canopy types. (Author).
Download or read book Pressure Distribution During Parachute Opening written by H. D. Melzig and published by . This book was released on 1966 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation and correlative analysis were conducted to determine the pressure distribution over the surface of parachute canopies during the period of inflation for the infinite mass case and to correlate pressure coefficients with inflating canopy shapes. Parachute canopy models of Circular Flat, 10% Extended Skirt, Ringslot, and Ribbon designs were tested under infinite mass conditions in a 9 x 10 ft low speed wind tunnel. External and internal pressure values were measured at various locations over the surface of the model canopies throughout the period of inflation, and generalized canopy profile shapes were obtained by means of photographic analysis. Pressure coefficients derived for the steady state (fully open canopy) are quite comparable to the results of previous measurements. Peak pressure values during the unsteady period of inflation were found to be up to 5 times as great as steady state values. The relationships between the pressure distribution and time for each of the canopy models deployed at free-stream velocities between 70 and 160 ft/sec. are presented.
Download or read book Dynamic Pressure Distribution on Parachute Canopies written by H.-D. Melzig and published by . This book was released on 1968 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted to determine the differential pressure distribution on the canopies of four types of parachutes (Circular Flat, 10 % Extended Skirt, Ringslot, Circular Flat Ribbon) during the period of inflation under finite mass conditions. In flight tests the differential pressure on the cord and the gore center line was measured with four pressure transducers distributed over the canopy in equal distances from the skirt to the vent.
Download or read book Parachute Canopies During Inflation written by H.-D. Melzig and published by . This book was released on 1963 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The pressure distribution across the canopy and its alteration whilst filling will be measured on 3.3 ft. models of 4 well-known types of parachute (Circular Flat, Extended Skirt, Ringslot, Circular Flat FIST). At the same time a method will be found of describing the changing canopy shape as it fills, and both results will be compared with each other.
Download or read book PARACHUTE CANOPIES DURING INFLATION written by H. D. Melzig and published by . This book was released on 1965 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation and correlative analysis were conducted to determine the pressure distribution over the surface of parachute canopies during the period of inflation for the infinite mass case and to correlate pressure coefficients with inflating canopy shapes. Parachute canopy models of Circular Flat, 10% Extended Skirt, Ringslot, and Ribbon designs were tested under infinite mass conditions in a 9 x 12 ft low speed wind tunnel. External and internal pressure values were measured at various locations over the surface of the model canopies throughout the period of inflation, and generalized canopy profile shapes were obtained by means of photographic analysis. Pressure coefficients derived for the steady state (fully open canopy) are quite comparable to the results of previous measurements. Peak pressure values during the unsteady period of inflation were found to be up to 5 times as great as steady state values. The relationships between the pressure distribution and time for each of the canopy models deployed at free-stream velocities between 70 and 160 ft/sec are presented in detail and correlated with changing canopy shape. A complete shape analysis is made and a mathematical model is proposed. (Author).
Download or read book Study of Parachute Forces and Canopy Pressure Distribution Measured in a Subsonic Wind Tunnel Under Infinite Mass Conditions written by Helmut G. Heinrich and published by . This book was released on 1972 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the purpose of parachute canopy stress analysis during the period of inflation, the pressure distribution measured on a ring-slot parachute model is related to the instantaneous parachute force. The correlation of pressure and force data is based on test results established at the Deutsche Forschungsanstalt fuer Luft-und Raumfahrt (DFLR), Braunschweig, Germany. The final pressure-force-time relationship incorporate individual as well as averaged test data. A fair agreement could be shown between measured forces and those obtained from numerical integration of differential pressure over the canopy surface.
Download or read book Pressure and Canopy Profile Data of 20 Conical Ribbon Parachutes During Inflation written by H. G. Heinrich and published by . This book was released on 1977 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sandia Laboratories, Albuquerque, N.M., established wind tunnel data of 3 ft ribbon parachute models concerning canopy profiles, drag forces and pressure distribution during the period of inflation. The data were analyzed at the University of Minnesota and resulted in presentations of canopy profile coordinates, drag areas and pressure distributions versus time. Pressure integration about the canopy surfaces as given by the established coordinates provided calculated areas which agreed satisfactorily with measured drag areas. Also, radial force coefficients of the various configurations were established. The results of this study are intended to serve as background information for related investigations such as studies concerning parachute dynamics, stress analysis, etc.
Download or read book Stress Analysis of a Parachute During Inflation and at Steady State written by Helmut G. Heinrich and published by . This book was released on 1965 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The stresses occurring in the cloth of an opening parachute and at steady state are calculated. The method is based on assumed instantaneous and steady state shapes and related pressure distributions. It is general and may be applied to any type and size of canopy built out of solid cloth. The presented analysis is limited to canopies constructed of triangular gores, but can be extended to other gore patterns. A numerical calculation is made for the Solid Flat, Circular Parachute during the opening and at steady state.
Download or read book Parachute Stress Analysis During Inflation and at Steady State written by H. G. Heinrich and published by . This book was released on 1969 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the period from 1965 to 1969, two new methods for stress calculations have been proposed and general remarks primarily concerning the elasticity characteristics of a parachute cloth and pressure distribution have been made. The conservative way of performing a parachute stress snalysis consists of first establishing the geometry of the parachute canopy and then applying a certain pressure distribution. Subsequently, the pressure distribution has been linked to the instantaneous parachute force which can be obtained from an opening shock calculation. In this manner one can possibly obtain closed solutions with a minimum of empirical factors. An example of this approach is presented in detail in the following chapters.
Download or read book Experimental Determination of Transonic and Supersonic Pressure Distribution and Mass Flow Accommodation for the Hemisflo Ribbon Parachute During Inflation written by Ronald J. Niccum and published by . This book was released on 1965 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of an experimental study to qualitatively determine the air flow through a Hemisflo ribbon parachute during the inflation process. These measured mass flows are analyzed relative to free stream velocity and density ratio. The results are presented as ratios of measured to inviscid flow through the canopy inlet area, thus giving a measure of the canopy's ability to accommodate the air mass entering the parachute mouth. Related to the mass flow studies, was the determination of pressure distributions on the internal and external canopy surfaces. Measurements were made at Mach 0.8, 1.2, and 3.0. In addition, several tests were conducted using an ogive forebody at two upstream locations.
Download or read book Experimental Determination of Transonic and Supersonic Pressure Distribution and Mass Flow Accommodation for Ribbon Parachutes During Inflation Volume Ii the 17 Geometric Porosity Hemisflo Ribbon Parachute and Circular Flat Ribbon Parachutes with Various Geometric Porosities written by Ronald J. Niccum and published by . This book was released on 1967 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented in this report of an experimental study to determine the air flow through several fully open circular flat ribbon canopies of various geometric porosities and a 17% geometric porosity Hemisflo canopy during its inflation. The measured mass flows are correlated with inviscid flow as a measure of the canopy's accommodation of the air mass available at the mouth inlet under specific operation conditions. In conjunction with the actual measurements of mass flow, the pressure distributions on the internal and external canopy surfaces were determined. These measurements were made on models with suspension lines as well as on models without suspension lines so that suitable estimates of suspension line effects could be made. Measurements were made at Mach 0.8, 1.2, and 3.0. In addition, several tests were conducted in the wake of an ogive cylinder located at two upstream positions. (Author).
Download or read book Investigation of the Flow Field During the Inflation of Clustered Parachutes written by R. J. Niccum and published by . This book was released on 1966 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clustered parachutes during the period of inflation were simulated by elliptical cylinders in potential flow and so-called O'Hara shape parachutes in water flow and wind tunnel experiments. The results are presented in the form of streamline and pressure distribution plots around the respective bodies. Results show that when geometric symmetry is disturbed, the flow field becomes unsymmetrical and strong attractive or repulsive forces are developed. This allows a variety of inflation modes to occur and, hence, poor cluster opening performance.
Download or read book Experimental Determination of the Subsonic Mass Flow Through Several Ribbon Type Parachute Canopies During Inflation and at Steady State Conditions written by Kenneth B. Buchanan and published by . This book was released on 1968 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of studies to determine the mass flow through circular flat ribbon canopies of several geometric porosities at steady flow conditions and during inflation and through 17% and 27% porous Hemisflo canopies during inflation are presented. Pressure distributions which were established as a necessary part of the study are also included. (Author).
Download or read book Dynamic Pressure Distribution on Parachute Canopies written by C. Saliaria and published by . This book was released on 1967 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pressure distribution on the canopies of several types of parachutes shall be determined under finite mass conditions. These types are the Circular Flat, the Extended Skirt, the Ring-slot and the Circular Flat Ribbon parachute. The pressure distribution during filling and at steady state shall be related to the instantaneous canopy profile. Furthermore, an attempt shall be made to establish a general relationship between canopy profile and pressure distribution. The snatch velocity shall be held constant at approximately 110 knots, while the canopy loading (W/S) shall be limited to the range between 0.3 and 0.7 lbs/ft2.
Download or read book Experimental Determination of Transonic and Supersonic Pressure Distribution and Mass Flow Accommodation for Ribbon Parachutes During Inflation Vol I the 27 Geometric Porosity Hemisflo Ribbon Parachute written by Ronald J. Niccum and published by . This book was released on 1965 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: The measured mass flows are analyzed relative to free stream velocity and density ratio. The results are presented as ratios of measured to inviscid flow through the canopy inlet area, thus giving a measure of the canopy's ability to accommodate the air mass entering the parachute mouth. Related to the mass flow studies, was the determination of pressure distributions on the internal and external canopy surfaces. Measurements were made at Mach 0.8, 1.2, and 3.0. In addition, several tests were conducted using an ogive forebody at two upstream locations. The wake of the ogive forebody with respect to pressure is analyzed. (Author).
